https://roosemotorsport.co.uk/media...er-td4-uprated-intercooler-330948805409-2.jpg
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GrumpyGel
Well-Known Member
Naked!
You can't just replace the plastic bumper with a tubular one.
Not unless you want it to look like that!
Hippo
Lord Hippo
If yer take away the plastic bumper yer reduce the crumple zone at the front. Part of the bumpers job is to absorb the energy in a crash. Not all of it but some of it. Yer would also got a lot of water flowing in to the engine bay if it were removed. Road spray and rain. Yer would need to reduce this or it will get int electronics over time.
GrumpyGel
Well-Known Member
Surely the plastic bumper ain't going to do anything in a crash other than fold. Its mainly screwed to even flimsier bits of plastic as well. I can't see it being integral to any crumple zone - but I'm no expert.
Nodge68
Well-Known Member
Anything between the crashing vehicle and what it hits will absorb energy. This is what a crumple zone is for. The bumper and it's armature form part of that crumple zone. So although the bumper is plastic. It still absorbs an amount of energy and transfer it to a larger area of the front. This helps slow the vehicle down a tiny amount. But in a crash, every little bit helps.
Don't forget that the plastic bumper hides that substantial armature, which is a crucial part of the crumple zone too.
Last edited:
Hippo
Lord Hippo
As nodge said above. But yer have to appreciate what the bumper does only works well at lower speeds. At 70mph it's a different story due to the forces involved. At 20mph you may get away with just bumper damaged and light bump to the metal behind if any. Although it seems easy to cut it's probably the right type of plastic to not shatter on impact. More a case of it folding/bending with force during impact to encase what's behind it so things don't go flying oft too much. Bit like below.
GrumpyGel
Well-Known Member
You don't need crumple zones at low speeds. The plastic bumper may or may not get damaged depending on what and how you hit it I suppose.
I still can't see how a plastic shroud is going to have any affect (other than minusculely small) to a crumple zone at the sort of speeds where crumple zones are needed. I'm sure it's not taken into account in the designers calculations - so therefore may be positive or negative - eg springiness is negative.
The armature underneath is a completely different and may be integral to crumple zone functionality. To unbolt that and bolt on a "tubular bumper" to replace it could have all sorts of implications. Similarly, leaving everything as-is but bolting on a tubular bumper in front of everything (through the plastic as an A Bar is) using mounts on the armature or other parts of the chassis will probably also have an impact.
However, those considerations are small considering the potential a bolted on lump of iron has to that child that runs out in front of you. The soft plastics and other design characteristics are made in great part to help reduce the impact of pedestrians in an impact. An iron bar will do the reverse!
I still can't see how a plastic shroud is going to have any affect (other than minusculely small) to a crumple zone at the sort of speeds where crumple zones are needed. I'm sure it's not taken into account in the designers calculations - so therefore may be positive or negative - eg springiness is negative.
The armature underneath is a completely different and may be integral to crumple zone functionality. To unbolt that and bolt on a "tubular bumper" to replace it could have all sorts of implications. Similarly, leaving everything as-is but bolting on a tubular bumper in front of everything (through the plastic as an A Bar is) using mounts on the armature or other parts of the chassis will probably also have an impact.
However, those considerations are small considering the potential a bolted on lump of iron has to that child that runs out in front of you. The soft plastics and other design characteristics are made in great part to help reduce the impact of pedestrians in an impact. An iron bar will do the reverse!
Hippo
Lord Hippo
There's a lot to crash testing and far more than I know. All sorts of advances have been made over the years like plastic headlights as opposed to glass. It's difficult to put into words to convince someone. The only option is to have a look at cars ont web with crash damage. Judge for yerself the speeds involved and if the bumper absorbed the energy. The theory of absorbing energy or spreading the energy to absorb with crumple zones is to reduce the stock impact to the car, and therefore the peeps inside. If yer drive into a lamp post head-on at 5mph the bumper on a FL1 will do it's job. I would say try it for yerself but it's not a good idea as it will hurt yer hippo. It all depends on the speed, angle of impact and what yer hit. Bumpers are partly there to look good, cover the front of yer car and to assist in a bump.
GrumpyGel
Well-Known Member
lol, I'll get Mrs Grumpy behind the wheel of the parts car, push it up to speed and tell her to drive into a lamp post. I'll and report back
Nodge68
Well-Known Member
It's a very complex subject, in which designers invest huge amounts time. The primary purpose of the bumper shell, is as the name suggests. So they are there to shrug off minor bumps and knocks, mainly when manoeuvring at slow speed. The fact that they are on the front will be calculated in any crash models when they are done. They won't do a huge amount in a typical MIRA crash test. However there would still be a measurable difference if tested with and without the bumper shell being there or not.
As already mentioned, the main bumper component is the armature underneath. That is part of the impact energy dispersion system and so must be present on the vehicle.
Interestingly many modern cars have an energy absorbing polyurethane foam behind the bumpers. This foam is there for one purpose. This is to absorb impact energy, even though it's only a few cm thick.
I'm surprised the facelift FL1 doesn't have a foam filled bumper, but it doesn't. Presumably as the crash testing and evaluation had already completed, adding it later would have required a retest at MIRA.
As already mentioned, the main bumper component is the armature underneath. That is part of the impact energy dispersion system and so must be present on the vehicle.
Interestingly many modern cars have an energy absorbing polyurethane foam behind the bumpers. This foam is there for one purpose. This is to absorb impact energy, even though it's only a few cm thick.
I'm surprised the facelift FL1 doesn't have a foam filled bumper, but it doesn't. Presumably as the crash testing and evaluation had already completed, adding it later would have required a retest at MIRA.
Nodge68
Well-Known Member
I don't personally think that the crash testing in Hippo's video are very fair, when compared to real world crashes. We don't on the whole, crash into deformable blocks, fitted to a non moveable mounting. This gives a rather distorted view of how a Freelander or anything else behaves in the crash test.
If a FL1 hits something like a Fiesta of comparable age, then the FL1 shows minor damage by comparison to the Fiesta. The mass of the FL1 in the MIRA test works against it, so it crumples quite badly. Simply because the impact is against a fixed and unforgiving object. If the FL1 impacts a Fiesta, at the same speed, then the FL1 looks much less damaged and the Fiesta is a complete mess. This is due to the crumple zones being designed to absorb the different masses of the 2 vehicles. The FL1 crumple zone is able to absorb more energy than the Fiesta's. So the FL1 apparently has little distortion and the Fiesta is a real mess. I used a Fiesta as my example because I have had a personal experience with both a FL1 and 2002 Fiesta that had an offset crash at a closing speed of 40 Mph. Sadly phone cameras weren't so common then, so no pictures exist of the damage.
If a FL1 hits something like a Fiesta of comparable age, then the FL1 shows minor damage by comparison to the Fiesta. The mass of the FL1 in the MIRA test works against it, so it crumples quite badly. Simply because the impact is against a fixed and unforgiving object. If the FL1 impacts a Fiesta, at the same speed, then the FL1 looks much less damaged and the Fiesta is a complete mess. This is due to the crumple zones being designed to absorb the different masses of the 2 vehicles. The FL1 crumple zone is able to absorb more energy than the Fiesta's. So the FL1 apparently has little distortion and the Fiesta is a real mess. I used a Fiesta as my example because I have had a personal experience with both a FL1 and 2002 Fiesta that had an offset crash at a closing speed of 40 Mph. Sadly phone cameras weren't so common then, so no pictures exist of the damage.
Hippo
Lord Hippo
Not my video. If it was it would have jumped over the block
I would agree crashing into a block isn't real world. I think they're looking at the crash performance from the other side of the fence. It's a known shape/size/weight to crash into for comparison. They're looking at how the car crumples and absorbs energy. If it doesn't then there's a problem. If it does crumple/absort correctly then it's considered safe or safer than those that don't.
They're also looking for intrusion into the cabin. Drivers feet/knee damage and how far back the engine/steering is pushed etc. In theory if you hit that block and your car absorbed more of the impact then the occupants will be less damaged. If it absorbs too much or in the wrong way then there's not enough strength or control of the crumple. They will be looking at the crumple area's to see if and how it crumpled. Also timing of the airbag being set oft and fired a second time to collapse slightly as yer hit it with yer head.
In the real world an offset in height of a few inches could make a big difference. So the only way to test vehicles is with a known impact for comparison. The betterer it performs on this test... then bettterer the chance it is a safer car to be in if yer crash. It would be difficult to create an agreed universal crash test with another car. If you were to pick a particular make/model then it's crashability would offset your cars results. I would think that makes the block test more reliable by default.
From the safety perspective the crumple/absorbing energy is trying to save lives by sacrificing the car. It's a shame to see a car wasted in a crash but when it's a mess its done it's job even if it's life it terminated suddenly.
I would agree crashing into a block isn't real world. I think they're looking at the crash performance from the other side of the fence. It's a known shape/size/weight to crash into for comparison. They're looking at how the car crumples and absorbs energy. If it doesn't then there's a problem. If it does crumple/absort correctly then it's considered safe or safer than those that don't.
They're also looking for intrusion into the cabin. Drivers feet/knee damage and how far back the engine/steering is pushed etc. In theory if you hit that block and your car absorbed more of the impact then the occupants will be less damaged. If it absorbs too much or in the wrong way then there's not enough strength or control of the crumple. They will be looking at the crumple area's to see if and how it crumpled. Also timing of the airbag being set oft and fired a second time to collapse slightly as yer hit it with yer head.
In the real world an offset in height of a few inches could make a big difference. So the only way to test vehicles is with a known impact for comparison. The betterer it performs on this test... then bettterer the chance it is a safer car to be in if yer crash. It would be difficult to create an agreed universal crash test with another car. If you were to pick a particular make/model then it's crashability would offset your cars results. I would think that makes the block test more reliable by default.
From the safety perspective the crumple/absorbing energy is trying to save lives by sacrificing the car. It's a shame to see a car wasted in a crash but when it's a mess its done it's job even if it's life it terminated suddenly.
GrumpyGel
Well-Known Member
Absolutely, it is very complex and I've often wondered how they engineer a monocoque chassis to crumple on impact but protect the cabin space. It can't crumple much cos there's a solid lump of metal under the bonnet.
There are definitely 2 areas of crumple - the high impact where the chassis crumples and the low impact where the bumper crumples, but by law shouldn't result in damage to the vehicle - I believe this is up to 5mph unless its different these days.
In a high speed impact, the low-speed crumple will go first, so I suppose that knocks 5pmh off the speed that the main chassis has to absorb - not inconsiderable and could make a difference. Bolting a tubular steel bumper on will add that 5mph back on - plus or less any difference its characteristics have to the std armature.
It will also be illegal in the UK - I'm pretty sure of that - it would be treated like bolting on a steel bull bar. Killers to pedestrians.
Agreed that those MIRA crashes are real world....
There are definitely 2 areas of crumple - the high impact where the chassis crumples and the low impact where the bumper crumples, but by law shouldn't result in damage to the vehicle - I believe this is up to 5mph unless its different these days.
In a high speed impact, the low-speed crumple will go first, so I suppose that knocks 5pmh off the speed that the main chassis has to absorb - not inconsiderable and could make a difference. Bolting a tubular steel bumper on will add that 5mph back on - plus or less any difference its characteristics have to the std armature.
It will also be illegal in the UK - I'm pretty sure of that - it would be treated like bolting on a steel bull bar. Killers to pedestrians.
Agreed that those MIRA crashes are real world....
GrumpyGel
Well-Known Member
That's how buildings are designed over here - they might not be habitable after an earthquake and need demolishing, but heavy bits won't (shouldn't) have collapsed/fallen and killed people.
Bricks and mortar may be safe as houses over there - but it a killer here
Hippo
Lord Hippo
The Euro NCAP results below make for interesting reading. The Freelander 1 achieved a score of 3 while the later newer design of the Freelander 2 scored 5.
Both the FL1 and FL2 are built using unibody construction. This is where the chassis is integrated into the body to reinforce it to give strength. Without this the body would have less torsional strength and the cabin would probably collapse more in a crash.
Freelander 1
link = https://www.euroncap.com/en/results/land-rover/freelander/15573
report - https://cdn.euroncap.com/media/9893/euroncap_land-rover_freelander_2002_3stars.pdf
Freelander 2
link = https://www.euroncap.com/en/results/land-rover/freelander/15728
report = https://cdn.euroncap.com/media/8782/euroncap_landrover_freelander_2_2007_5stars.pdf
Both the FL1 and FL2 are built using unibody construction. This is where the chassis is integrated into the body to reinforce it to give strength. Without this the body would have less torsional strength and the cabin would probably collapse more in a crash.
Freelander 1
link = https://www.euroncap.com/en/results/land-rover/freelander/15573
report - https://cdn.euroncap.com/media/9893/euroncap_land-rover_freelander_2002_3stars.pdf
Freelander 2
link = https://www.euroncap.com/en/results/land-rover/freelander/15728
report = https://cdn.euroncap.com/media/8782/euroncap_landrover_freelander_2_2007_5stars.pdf
teddywood1
Well-Known Member
and me and my wife know all about the earth quakes over there.That's how buildings are designed over here - they might not be habitable after an earthquake and need demolishing, but heavy bits won't (shouldn't) have collapsed/fallen and killed people.
Bricks and mortar may be safe as houses over there - but it a killer here
Hippo
Lord Hippo
Note how the rear bumper is a mess because it sacrificed itself by absorbing as much energy as possible.
Rich in Vancouver
Well-Known Member
The bumper may have sacrificed itself but it sure made a mess of the lorry it backed into!
